Torque and speed transmission device



March 28, 1939. o. E. SZ EKELY TORQUE AND SPEED TRANSMISSION DEVICE Original Filed Nov. 19, 1934 e Sheets-sheet i .w e m M E m ,0

Original Filed Nov. 19, 1934 a Sheets-Sheet 2 lg. V

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March 28, 1939. o. SZEKELY TORQUE AND SPEED TRANSMISSION DEVICE Original Filed Nov. 19, 1934 6 Sheets-Sheet 3 March 28, 1939.

o. E. SZEKELY 2,151,722

TORQUE AND SPEED TRANSMISSION DEVICE 6 Sheets-Sheet 4 Original Filed NOV. 19, 1934 GUM; o

March 28,1939. o. E. SZEKELY TORQUE AND SPEED TRANSMISSION DEVICE bri inal Filed N $v. 19, 1934' e Sheets-Sheet 5 March 28, 1939. o. E. SZEKELY 2,151,722

TORQUE AND SPEED TRANSMISSION DEVICE Original Filed Nov. 19, 1934 6 Sheets-Shea; 6

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Patented Mar- 28, 1939 PATENT orricr.

2,151.72; 'roaorm AND srssn TRANSMISSION navro Otto Edward Szekely, Elmira, N. Y., assignor to The SIekely Company, Inc., a corporation of New York Application November 19, 1934, Serial No. 753,755 I Renewed April 12, 1937 26 Claims. This invention relates to improvements in torque and speed transmission devices including speed and torque selector transmitting systems.

[One of the features of the present invention is the provision of such a system with a low-speed drive train for attaining a quick starting at a high torque delivery, together with a variable ratio transmission for producing the ultimate high speed.

Another feature of the present invention-is the provision of a low speed and high torque drive train operative for quickly starting the driven element, together with an automatically variable high speed and low torque transmission for nor- 7 mal driving, together with selector means responsive to the torque demand for determining the operation of said trains. V

g A further feature of the invention is the provision of a low speed and high torque drive train for producing a quick starting at high torque demand, a high speed and low torque train of variable ratio for producing the normal drive and cooperating with said low speed drive at high torque demands.

Still another feature of the invention is the provision of a low speed and high torque drive, a variable ratio high speed and low torque drive for normal operation independently, of the low speed drive, and'automatic devices for superseding the low speed drive with the high speed drive at low torque demands, and for varying the ratio in accordance with the torque'demand.

Astill further feature of the invention is the provision of a low speed and high torque train for producing a constant drive effort and including a clutch which is overrun at higher speeds, together with a variable ratio train including devices for automatically selecting the ratio according ,to the torque demand, 'and also including means for-disconnecting the trains from the source source.

Still another feature of the present invention is the provision of a low speed and high torque train including a clutch which is overrunat higher speeds, a variable ratio .trainrresponsive to the torque demand for driving the driven element ata speed greater than that determined by said low speed train, and a positive and mechanical reverse train, with means for positively disconnecting the high speed and low speed trains when theireverse train is engaged, and

vice versa.

A still further feature of the invention is a provision of a low speed and high torque train,

of power at low speeds ofthea variable ratio train, a reverse train, and a selector structure turning with the driven element and having relatively few and light parts so that the inertia of movement thereof is small.

A still further feature of the invention is the provision of a transmission of the said type which is composed of simple and easily manufactured and assembled parts, and which is capable of use even upon breakage of automatically selecting elements of the drive trains.

substantially on line 2-2 of Fig. l.

- Fig. 3 is an upright viewof the same substantially on line 3-3 of the same.

Fig. 4 is an upright transverse sectional view of the same substantially on line 4-4 of the same.

Fig. 5 is a detail sectional view, on a larger scale, substantially on line 5-5 of Fig. {1.

Fig. 6 is a longitudinal upright diametrical section, on av larger scale, showing the differ-' entiating gearing and the retarding structures.

Fig. l is a similar view, showing the direction and torque selector assembly.

Fig. 8 is a view 'of.the parts shown in Fig. '7, substantially on line 8-8 of Fig. 4.

In' these drawings, the engine E has connected thereto the housings Hi and H2, and on these are successively supported the housings H3, H4, and H5 which together form an oil tight closure. The-assembly may be supported, also, at other points in any desired manner. The housing H5 is illustrated as having a spherical form for cooperation as a part of the usual universal joint structure. The top of housing H4 is-open and receives a plate H6 for the shift control system,- and this in turn supports a closing member H1.

The engine E has a flange Ill on the end of its crank shaft which is connected by bolts II with. the fly wheel l2. A fly wheel ring I! sup- I! are preferably constructed and preliminarily adjusted to preserve the static and dynamic balance of the system which turns with the engine shaft. The outward centrifugal movement of weights I8 is against the action of the return springs I8, and causes a movement of the annular pressure plate It toward the left in Fig. l. Thispressure plate is carried in rotation with the fly wheel by the engagement with a splining member l2a thereof.

A- clutch disk 20 extends between surfaces of the fly wheel l2 and pressure plate I! and is provided with friction material 2| at its faces for engagement with these surfaces. The clutch disk 20 is supported on a collar 22 which is splined to a clutch shaft 23, this clutch shaft having a forward extension 24 supported for rotation in the end of the engine shaft and its flange I l. The

clutch shaft 28 extends through the web wall His and has an anti-friction bearing Bl for supporting it with respect to this web wall, and is paclred by a gland 26.

As. shown in Figs. 1, 2, 3, and 6, the clutch shaft 23 has splines for positive driving connection with one end flange III of the retarding structure which is illustratively shown as an oil displacement pump of rotative gear type. The pump housing II and the other pump flange 32 are connected tightly-to the flange III by bolts lla. The end flange 32 has a cage-like extension 83 to which is rigidly connected an apertured end web 84 formed integral with a supporting sleeve 35 which is supported by an anti-friction bearing B2 carried by the housing section H4, and provided at its outer end with splines for fixed driving connection with a torque limit drive gear 36 (Figs. 1, 'l, and 8). The first flange 88 of the pump has a cylindrical end flange 31 through the interior of which oil may flow on its way'into the pump, passing through ports 38. The flanges I and 82 support the pivots 88 for the pump pinions 48 (Figs. 2 and 6) which latter flt closely in corresponding pockets in the housing 3 I During operation of, the pump as a displacement means, the fluid is'disoharged through the outlet passages 42 having the threaded restriction plugs 43 therein.

Cooperative with the cylindrical flange 31 are the spaced flanges 44, 44a shown asintegral with the web wall Hla. This web wall ma also is provided, beneath the axis of theushafts, with a passage 48 by which oil may be drawn from the sump formed by the bottom of the housing section H8.

The pump pinions 4| cooperate with an inner pump gear 48 which is splined to a sleeve 41 journaled on a bearing bushing 41a supported by the clutch shaft 28. The sleeve 41 has a radial end flange 48 and is guided within the end flange 82 by an anti-friction bearing B8. The end 48 carties the pivots II for the planet pinions-Il of a differentiating gear train. The small inner sun gear 52 of this diflerentiating train has a cylindrical internal clutch surface is and is connected by'splinesto the end of the clutch shaft 28. A

thrust plate 84 operatu. between the flange 48 andthe sun gear I! as a spacing member. A large internally cut gear I of the differentiating train is fixed toaradial flange it of the supporting sleeve 81 which extends within the small sun gear 82 and is provided with clutch surfaces II for cooperation with the rollers I. of thisclutch. A bearing bushing 38 is employed for holding the two sun gears in concentric relation. v

Anng II supports the endsofthe planet pinion pivots it and is connected to the flange 48 by posts 8 I a from point to point.

The transmission shaft 62 is splined for flxed engagement with the sleeve 51, and has an extension 62a for holding it in axial alignment with the clutch shaft 23, and at the other end is provided with clutch teeth 84 which are operative during forward driving movement.

As shown in Figs. 1, 4, '7, and 8, the torque limit drive gear 36 is in mesh with a large torque counter gear which is formed integral with a small torquecounter gear ll, these gears'being supported by a bearing bushing 12 on the fixed bearing pin'l3 carried by the housing section H4, and illustrativeiy located directly beneath the axis of shaft 62 and turning in a maintained pool of oil so that the lubrication of associated parts is assured.

A direction and torque selector assembly includes a body 14 having clutch teeth cooperative with clutch teeth 64 and being mounted on splines of the tail shaft I6 so that the body'14 may slide axially while turning with the shaft. The end of shaft 16 has an extension 16a within the transmission shaft 62 to assure co-axial alignment of these parts, and is provided with an anti friction bearing B4 carried by the housing section H4. The tail shaft 18 has abutments 16b engaged with the inner race of the bearing B4, and has a clamping nut 18c likewise engaged with this inner race for assuring the proper axial positionof the tail shaft I8.

As shown in Figs. 4 and -7, the exterior of the body 14 has clutch surfacestil for cooperation with the clutch rollers 8| of an overrunning clutch which operates, when engaged, to determine the maximum. torque and mi;'.imum.speed ratio of the transmission. An outer body 82 has a cylindrical internal clutch surface for cooperation with'the rollers 8i so that the outer body 82 may turned freely in one direction about the axis 8!. This outer body, further, has gear teeth am.

A reverse gear 86 is held by splines of the inner body 14 and carries a guide bushing 81 located between itand the outer body 82.

The shift lever 88 has a pivot ball 89 which is pressed upward against a socket 90 by a pressure spring ill. The socket 90 is held in position by a threaded clamping collar 92. The lower actuating end 93 of the shift lever extends intoa socket piece 84 flxed to the selector rod 95 which has notches 86 therein. Three notches are shown, corresponding to the forward, neutral, and reverse positions of the shift lever 88. These notches cooperate with the detent ball 91 (Fig. 4) which is urged into detaining position by a, spring 88.

The reverse idler shaft I00 is mounted in the housing section H4 and has a large gear Hit in plane with and in-mesh with the large torque counter gear 18 (Figs. 4 and 8), and also has a small reverse idler gear I02 which is positionedeffects in the pump; so that this effect may be and having a top aperture in communication with the interior of the housing section H3. This aperture may be closed by a valve closure mem ber Ill fixed on a sliding valve stem 2, and normally seated by the valve spring H3. The valve stem H2 is provided with a piston H4 within a cylinder H I likewise formed in the housing section H3, and closed at its upper end by a plug H6 through which extends the upper end of valve stem H2. A connection Ill leads to the manifold of the engine, so that a reduced pressure prevails above the piston 4 when the engine suction increases. This reduced pressure operates to'raise the piston H4 and thereby lift the valve closure member Ill from its seat and permit air to enter, from the interior of housing section H3, into the cavity [i and thus break the vacuum being created in the rotating pump parts, so that liquid is no longer sucked through the housing passage 45. A connection H8 is also provided for the manual movement of the valve stem H2, and for adjustment of its prevailing position. It will be understood that if this ad- Justment is so made that the valve closure member III is seated during the normal operation of the system, the structure will tend to be .flerce produces an exceedingly rapid acceleration, due to the relative incompressibillty of the liquid. On

the other hand, if the adjustment be so made that the valve III is slightly raised above its seat during normal operation, so that a very small quantity of air is permitted to be drawn in, along with the liquid, a more compressible mixture of liquid and air is-present in the pump, and hence the startlngds softer and the rate of acceleration is less. This adjustment, therefore, determines the smoothness and rate of acceleration.

The space of cylinder H beneath the piston H4 is preferably provided with an air port H9 so that the engine manifold pressure accurately determines the movement of piston I H.

The operation of the system is as follows:

,When the tail shaft is at a standstill and the. engine E is turning at a low rateof speed, the flywheel l2 and pressure plate l9 are disengaged from driving relationship to the clutch disk 20. The clutch shaft 23, the pump housing and pump pinion, all parts of the differentiating train, and the torque limit drive gear 36 are at a standstill. If the direction and torque control assembly is in Forward" position as shown in Fig. 1, the clutch engagement at 64-15 holds the differentiating and pump parts and clutch shaft 2 3 at a standstill. If the assembly isin Reverse" position (Fig. 8), the reverse drive train holds the differentiating and pump parts with clutch shaft 23 at a standstfll. Q

To start the forward movement of the tail shaft 16,. the assembly is brought into the Forward" position. The engine is speeded up so that the centrifugal weights l6 operate to cause enga ement between the fly wheel I2 and pressure plate I! with the friction surfaces provided on clutch disk-20. The clutch disk now rotates the clutch shaft 23 in a direction and at a speed determined by the engine movement, and thus the pump 1 structures including the end flanges 3g and 32 wise, the inner differentiating sun. gear 52 is rotated at this angular velocity. If the resistance to movement of the tall shaft 16 is great.

this tall shaft is driven through the train 3B--'ll|-||82-8l-80--I4'l8 at a low speed and at a high torque effect. Therewith the clutch the'lnner' pump gear 48 ata rate of speed which.

is one-half the difference between the rates of speed 01' the two gears I2 and 55. I The inner pump gear 48 thus turns in the same direction as the housing It but at a lesser angular velocity, and the pump pinions" rotateand cause a delivery of fluid. This delivery of fluid is restricted by the plugs 43 in the outlet passages. If noth: ing but air is being pumped, this retardation is minor and the system is free to turn without exerting any substantial torque eifect upon the tail shaft 16 which is suflicient to cause a rotation of this tall shaft.

However, the, change in manifold pressure by opening the throttle valve causes the valve closure member I I I to be substantially seated, so that the suction break is no longer present, and liquid is drawn, by the pump, through the inlet passage 45 and through the ports 38 and thus delivered from the, pump through the outlet passages 42'.

The retardation upon the liquid is greater than the retardation upon the gas, and hence there is an effect in the pump which tendsto bring the internal pump gear 46 up to the speed of the pump housing, 'the corresponding reaction being applied to the pump housing itself, and in the direction of its rotatlom v This increased speed of the internal pump gear 46 is accompanied by a like increase in the speed of the flange 48 and in the bodily movement of the planet pinion pivots 58, so that these planet pinions are being carried bodily about the axis of flange 48 at a greater rate than that previously determined by the then-existing difference of speeds of the inner and outer gears 52 and 55.

This causes a turning movement or torque to be exerted upon the large gear 55 so that a turning effect is produced at the clutch teeth 64-15 tending to move the assembly'body l4 and the tail shaft 16 in the same direction as the engine movement. The amount of the torque elfect thusbeing turned at a minimum speed controlled by the relative gear ratios as described above, the aforesaid drive through the pump system tends to become balanced by the action of the differentiating train so that part of the effective torque is being delivered through the minimum speed train while part is being delivered through the pump and differentiating system. If the torque demanded by the. tail shaft 18 is less than the torque which is transmitted through the pump and difierentlatingsystem, the torque delivered at the tail shaftis greater than'that demanded,- and hence the tailshaft velocity tends to increase. 'iii. the transmission is employed in an automobile,- this increase continues until the resistances opposing a free rotation of the tail shaft [6 (such as wind and road resistance, grades, and friction of parts) raises the demand to the transmitted output through the pump and differentiating system. A point of equivalence is thus automatically attained on the basis of the actual torque demanded at the tail shaft 18 itself. If the transmitted torque is sufficient to bring the tail shaft up to the speed of the engine, then the overrunnlng clutch elements 53-48-58 engage and prevent the tail shaft from exceeding the angular velocity of the engine. At this time,

-the pump and differentiating system operate to maintain this maximum speed ratio, and the speed of the tail shaft .increases withthe engine speed until the engine torque output equals the demand at the tail shaft. This condition may be referred to as "direct drive, as the tail shaft responds in speed exactly with changes in engine speed.

This-is the normal condition for operation in an automobile, for example, and the differential train and pump parts turn together at the same angular velocity, in the several anti-friction bearings provided for these parts. The body I4 continues to overrun the gear 82, by the operationof the overrunning clutch. The automobile responds directly in speed to the engine speed as determined by the accelerator pedal.

The employment of the overrunning clutch HI-ll preserves the structure against breakage upon excessive load. Thus, in the absence of such a restricting device, a drop of the load at the tail shaft I. might cause an acceleration of the parts beyond the engine speed: such a conpump and dlflerentiatlng parts. If the automobile encounters a heavy grade, for example, the torque demandedat the tail shaft becomes greater than can be supplied by the engine at the particular speed. The engine therefore tends to slow down if the same throttle opening is continued. Dependent upon the torque curve of the engine, the engine may for a time be able, or may immediately be unable to supply the necessary torque. Assoon asthislnabilityoccurs,the.torque demanded through the pump and differentiating parts causes a slippage in the pump so that the parts thereof no longer turn at the same angular speed, and differentiation occurs in the diiferentiating gearing so that automatically a new speed and torque ratiod's set up which is intermediate between the high speed and low torque ratio at "direct drive" and the low speed and high torque ratio established through the maximum torque train. Since this is produced as a result of the torque demand, the system is fully automatic,

and a new ratio is produced when the total torque demand of a system and automobile, as modified by, the gear ratio being produced in the differentiating g aring, is again equivalent to the engine speed and torque output.

[torque limit train through gears 88 and II is The low speed and ning the gear 82.

At an excessively high torque demand, the

pump system and differentiating gearing cannot establish a torque ratio which is high enough to attain such equivalence, so that the speed of the body It tends to fall below the speed determined through the limit train including gears 36 and II, and this latter drive now takes charge, and determines a minimum ratio of engine-totail shaft speeds, and so long as liquid continues to be pumped in the pump system. If the high speed drive through the pump system should tend to become higher, it is not able to supply the high torque demand and hence slows down to this limit speed ratio.

If a still further and higherdemand is made upon the tail shaft 16 than the ratio established at the speed determined by the operation of the limit train including gears 36 and 10, the source of power is further slowed down. The engine however is now operating under conditions which cause, a'higher suction effect in the intake manifold. This is communicated to the piston H4, and the latter rises and opens' the valve closure member Hi, thus admitting air-to the fluid displacement means, and substantially reducing or terminating the action-reaction effects in the high-speed system, so that the drive continues at the rate determined positively in the low-speed train.

As the demand increases further, the engine speed drops still further. With an internal combustion engine, the torque-speed ratio is usually such that upon decrease below a certain minimum speed, the torque output falls rapidly. At this time, however, the automatic clutch system opens, as the engine speed is no longer sufficient to cause the centrifugal weights ii to hold this automatic clutch closed. Thus, the transmission system ,is disconnected from the engine, and the engine cannot be dragged to a standstill.

In order to reverse the movement of the tail shaft IS, the torque and direction selecting'system is moved out of fforward" position into reverse position (Fig. 8). 'When the engine is revolving at suflicient speed, the automatic clutch again engages and turns the pump housing and differentiating gearing. The train through these structures is however interrupted by disengagement of the clutch elementsN-IS. The rotation of the end flange 34 of the pump structure causes a continued movement of gear 36 and therewith of counter-shaft gear It in the same direction as before, but since gears H and "a are out of engagement, this produces no movement of the tail shaft. The operation of moving the assembly into "reverse" position, however, has brought gear III of the reverse counter-shaft into mesh with gear It, so that a drive occurs from gear 35 through gear III to reverse gear II, for turning the reverse counter-shaft, and gear I02 now causes a movement of the gear l6 and thus of thebody ll in the reverse direction, turning the tail shaft 16 with it. It will be noted that this drive ceases when the engine slows down, by reason of the opening of the automatic clutch.

when the selector system is in "neutral position, all three trains (the high-speed lowtorque train through clutch elements 15, the low-speed high-torque limit train through gears IL-42, and the reverse train through gears Hit-48) are all disconnected. A racing of the engine under these conditions may cause the centrifugal weights to move and cause rotation of drop to idling speed, and causes an opening of the clutch shaft 23, the pump structures, and parts of the difl'erentiating train, but there is no present load on these structures, and the movement is substantially free, and no-movement of r the tail shaft l6.can be produced.

It will be noted that the system operates entirely automatically when in forward" position,

and that the driver has a normal control of the speed through the operation of the accelerator, and that release of the accelerator permits the pump parts to turn freely, permits the engine to system, so that there is smoothness of engagement and absence of excessive strain upon the automatic clutch.

Furthermore, it will -be noted that even in the event of rupture or breakage in the liquid supply system, so that thepump parts turn freely with respect to one another, it is possible to maneuver the automobile to a repair point, at the low speed determined through the maximum torque drive, both for forward and reverse movements. While the invention has been described with respectto a presently preferred embodiment, it

will be understood that it may be employed in many ways within the scope of the appended claims I claim:

1. A power driving system including a driving element, a driven element and transmission means connecting said elements; said transmission means including devices providing. a low speed and high torque ratio, train-connecting the driving and driven elements and. including an overrunning clutch, and a train connecting the driving and driven elements and'including first devices for operating at inversely variable speed and torque ratios and second devices in said train having relative slippage at a predetermined torque transmission therethrough and cooperating during slippage with said first devices for determining the torque ratio established insaid first devices.

2. A systemasin claim 1, in which said first devices operate to increase the velocity of the driven element above the velocity of the driving element at a low torque ratio of transmission,

and including means for preventing the driven 7 element from turning at a rate greater than a predetermined ratio to said driving element,

3. A power drivi'ng'system including a driving element, a driven element, and transmission means connecting said elements, said transmission means including a first system providing a low speed and high torque ratio train connecting the driving and driven elements and including and a second member operating through the an overrunning clutch, and a second transmission system including differentiating gearing having a first member connected to the driving element.

with said that transmission system for determining the torque ratio of transmission from the driving element to the driven element.

4. A power driving system including a driving element, a driven element; differentiating gearing including a large gear connected to the driven element, a small gear connected to the driving.

element, planet pinion means meshing with said gears. a member rotatable relative to said gears and having pivot means thereon for said planet pinion means; fluid displacement means including parts connected to the driving element and parts connected to said relatively'rotatable member, and means for creating a back pressure at said fluid displacement means; and speed reduction gearing connecting the driving element to the driven element and including an overrun,- ning clutch.

, 5. A power driving system, including a driving element, a driven element; difierentiating gearing including a large gear connected to the driven element, a small gear connected to the driving element, planet pinion means in mesh with said gears, and a relatively rotatable member having pivot means for said. planet pinion means; retarding means operative between the driving element and said relatively rotatable member tending to cause said element and member to turn at the same'speed and permitting slippage therebetween at a predetermined maximum torque; and speed reduction gearing connecting the driving element to the driven element and including an overrunning clutch. g

' 6. A power driving system, includingla driving element, a driven element, a low speed and high torque ratio train connecting the driving and driven elements and including an overrunning clutch for permitting the driven element to turn taster than the speed determined by said high ment, a second said member being connected through the overrunning clutch to the driven element, the third said member being connected through said ratio-varying devices to said driving element. I

'l. A power driving system for a source having,

a dropping torque characteristic when the velocity drops below a predetermined minimum,

including a driving element, an automatic clutch operated by and responsive to the speed of such source for coupling at a predetermined minimum speed and for uncoupling when the source is turning at less'than said minimum speed, a driven element, a low speed and high torque ration transmission system connecting the automatic clutch and driven elements and including an overrunning clutch, and a variable torque ratio transmission system connecting the'auto-' matic clutch and the driven element and includ- -ing gearing for causing the driven element to overrun the driving element 01' said overrunning clutch at high speed and devices responding to V increases of torque demand for successively increasing the ratio of torque transmission-and decreasing the ratio ofspeed transmission by said gearing until said ratio of speed transmission equals the ratio of speed transmission overrunning clutch, and a variable ratio train connecting the driving and driven elements and including devices responsive to the torque demand at the driven element for varying said ratio, and means actuated by the engine suction and operating through said devices for controlling the torque transmitted through said variable ratio train.

9. A power driving system including a driving element, a driven element, a torque and drive selecting assembly body connected to the driven element and movable between forward and reverse positions. a first gear connected to said driving element, a second gear revoluble relative to said body in one direction, a first countershaft having gears in mesh with said first and second gears when the body is in forward position and operative for reducing the speed and increasing the torque of the second gear relative to those of the driving element, an overrunning clutch for connecting the second gear and body at a low speed of the body, a variable ratio train connecting said driving element and'body and including a direct drive clutch which is connected when the body is in forward position, a third gear fixed on said body, a reversing countershait having gears thereon in mesh with a gear on said first counter-shaft and with said third gear when the body is in reverse position, and devices for changing the ratio of said variable ratio train.

10. A power driving system, including driving and driven elements, a low-speed and hightorque ratio train connecting the driving and driven elements and including an overrunning clutch, a high speed and low torque ratio transmission including gearing operative at difierent eflective speed and torque ratios for connecting the driving and driven elements and including devices having relative slippage at a predetermined maximum torque transmission and cooperating during such slippagev with the gearing for producing an increased torque ratio of transmission therethrough, said transmission including first means for connecting the driving and driven elements preparatory to forward movement and for disconnecting the driving and driven elements, and devices providing a reverse train connecting the driving and driven elements and including means coordinated with said first connecting means for connecting the driving and driven elements only when said first means is disconnected.

11. A power driving system including a driving element, a driven element, and transmission means connecting said elements; said transmission means including devices providing a low speed and high torque ratio train connecting the driving and driven elements and including an overrunning clutch, and a variable torque ratio train connecting the driving anddriven elements and including devices having relative slippage at a predetermined maximum torque transmission therethrough and also including devices for preventing said driven element from turning faster than a predetermined ratio with respect to said driving element.

12. A power driving system including a rotatable driving element, a rotatable driven element, a third element rotatable relative to said driving and driven elements, sun gears on said driving and driven elements, planet pinion means carried bodily in rotation with said third element, and braking means including a gear pump having a rotatable housing connected to said driving element, and meshing gears, one of said gears being connected to and driven by said third element, and another of said gears being mounted eccentrically in said housing and driven with said driving member, and means for determining the back pressure of fluid at said gear pump.

13. A power driving system including a driving element, a driven element, and transmission means connectin said elements;' said transmission means including a low speed and high means including devices on said driving element and said support element and means cooperative therewith-for determining the torque transmission between said driving element and. said supporting element by said fluid displacement means.

14. A power driving system including in combination with-a source of mechanical power having a rotatable driving member and including means responsive to-the rate of development of power by said source, of a driving element connected to said driving member and rotated thereby, a driven element providing a rotatable output member connected to a load, a low speed and high torque ratio train connecting the driving and driven elements and including an overrunning clutch, a variable ratio train connecting the driving and driven elements for turning the driven element when the torque demand of the load is less than equivalent to the torque output of the source and then operating'with overrunning of, said clutch, devices included in said variable ratio train for varying said ratio according to the torque demand of the load, and means actuated by said responsive means for controlling the torque transmission through said variable ratio train.

15. A system as in claim 14, including means responsive to the rate of speed of the source and and driven elements and including an overrunning clutch, a variable ratio transmission including diflerentiating gearing and braking devices operative between members of the differentiating gearing for controlling the relative speeds of'said differentiating gearing and operative at lowtorque demand of, said driven element to increase the velocity ratio thereto through said gearing and at high torque demand to increase the torque ratio thereto through said gearing and operative at velocities greater than the velocity ratio driven element to turn at low speed, and a variable ratio second gearing connecting said driving ments for causing said driven element to turn at low speed, and a second gearing connecting said driving and driven elements for causing the driven element to turn at a higher speed, said second earing including difi'erentiating gearing for causing said driven element to be driven at the speed of the driving element when the parts of the differentiating gearing turn at the speed of the driving element, and means including a structure carried by the driving element and a structure connected with the difl'erentiating gearing for causing the parts of the diflerentiating gearing to turn at the same speed.

19. A power driving system including a driving element, a driven element, a low-speed hightorque mechanical gearing connecting said ele ments for causing said driven element to turn at low speed, and a second gearing connecting said driving and driven elements for causing the driven element to turn at a higher speed, said second gearing including difierentiating gearing including small and large sun gears, respectively connected to the driving and driven elements for causing said driven element to be driven at the speed of the driving element when the parts'of' the differentiating gearing turn at the speed of the driving element, and means including a structure carried by the driving element and a strucferentiatinggears which turn relative to one.

another while driving is being accomplished at said one ratio; and means eilective tor-causing the difierentiating gears to turn at thesame speed and thereby causing the system to operate at said high speed ratio, said means. including elements which slip relative to one another when the torque demand at the driven element is in excess of a predetermined maximum.

21. A power driving system as ,in claim 20, in

which the means comprises .fluid displacement means and means for determining the back pressure upon said fluid displacement means.

22. A power driving system including a driving element, a driven element, and gearing fon providing at least two mechanical ratios of drive between the said elements; one said ratio being a low-speed high-torque ratio drive for causing the driven element to turn at a low speed and another said ratio being a high-speed low-torque ratio drive for causing the driven element to turn at a high speed, said gearing including differentiating gears which turn relative to one another 1 while driving'is being accomplished at said one ratio, clutch means connected'to the differentiating gears for 'preventing a first gear thereof turning faster than a second gear thereof and per? mitting said second gear to turn faster than said first gear whereby the relative rotation is permitted while driving at said one ratio, and means efiective for causing the differentiating gears to turn at the same speed.

23. A power driving system including a drivof the gears of said diflerentiating gearing, and

means responsive to"the power demand at said driving element for releasing said means.

24. A power driving system including a prime mover having a decreasing torque characteristic at successively lower speed, a driving element connected to said prime mover, a driven element, and gearing connecting said elements; said gearing including a low-speed high-torque ratio mechanical drive between said elements and a highspeed low-torque ratio mechanical drive between said elements, said latter drive including relative speed restricting means which is effective when engaged for causing the driven element to be actuated through said high-speed ratio drive and when released to permit the actuation of said driven element through said low-speed drive, and means responsive to the speed and power demand at said prime mover for releasing said restricting means when the load demand upon said driven element is greater than a predetermined maximum. o r

25. A power driving system including an inter- -nal combustion engine having a supply manifold,

a driving element connected to said engine, a

- driven element, and gearing connecting said'elements; said gearing including a low-speed hightorque ratio mechanical drive between said ele- 'ments and a high speed low-torque ratiomechanical drive between said elements, said latter drive including means which is effective when engaged for causing the driven element to be actuated through said high-speed tioned meanswhen said' pressure attains a predetermined ratio to atmospheric pressure.

26.vA power driving system including a driving element, a driven element, speed reduction gearing connecting said elements for causing said driven element to turn at low speed and including an overrunning clutch for permitting the driven element to turn faster than the ratio of drive through said gearing, and a variable ratio second gearing having a differentiating gearing including parts connected to said driving and driven elements and a further part driven at a speed dependent upon the diflerence of speeds of said driving and driven elements, and 5 means connected to said further part and to said driving element for controlling the relative speed thereof.

- O'I'IO EDWARD SZEKELY. 

